Image forming apparatus

ABSTRACT

An image forming apparatus includes: an LED print head exposing a photosensitive drum with light; a door arranged on one end side of the LED print head; a support portion for the LED print head operating in conjunction with opening and closing movements of the door, positioning the LED print head at a first position for exposing the photosensitive drum when the door is closed, and positioning the LED print head at a second position more apart from the photosensitive drum than the first position when the door is open; and a guide portion formed on the door and guiding a cleaning member to the LED print head, the guide portion having a first inclined surface which is lowered toward the LED print head so that the cleaning member is continuously held in contact with the LED print head under a state in which the door is open.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an image forming apparatus of anelectrophotographic type, such as a copying machine, a printer, or afacsimile, to which a light-emitting element array is mounted.

Description of the Related Art

An image forming apparatus of an electrophotographic type such as aprinter or a digital copying machine may include an LED print headserving as a light source configured to expose a photosensitive drumwith light. The LED print head is an exposure light source including apredetermined number of LEDs arrayed in a direction intersecting arotation direction of the photosensitive drum. That is, thepredetermined number of LEDs are arranged at different positions in thedirection intersecting the rotation direction of the photosensitivedrum, and each LED forms one pixel in this direction. The LED print headoccupies a smaller volume in the apparatus as compared to a laserscanner unit (hereinafter referred to as “LSU”) using a rotary polygonmirror, and a motor is not required in the LED print head. Therefore,the image forming apparatus using the LED print head can attain aneffect of downsizing and noise reduction as compared to the imageforming apparatus using the LSU.

The LED print head needs to be arranged closer to a surface of thephotosensitive drum as compared to the LSU. Therefore, toner is liableto adhere to the LED print head. When the toner adheres to a surface ofthe LED print head, an exposure light amount from the portion of the LEDprint head, to which the toner adheres, to the photosensitive drum isreduced. Therefore, occurrence of image defects such as densityunevenness is concerned. Consequently, it is necessary to regularlyclean a head surface of the LED print head with use of a cleaningmember. For example, in Japanese Patent Application Laid-Open No.2010-230954, there is disclosed a cleaning member including a cleaningpad configured to rub a light exit surface of an LED print head. On asurface of the cleaning member on a photosensitive drum side, there isprovided a protection member configured to rub a surface of thephotosensitive drum. The cleaning member slides in a longitudinaldirection of the LED print head under a state in which the cleaningmember is sandwiched between the photosensitive drum and the LED printhead. With this action, the cleaning member is capable of cleaning thelight exit surface along the longitudinal direction of the LED printhead without being separated from the light exit surface of the LEDprint head.

With regard to the cleaning member of the image forming apparatusdisclosed in Japanese Patent Application Laid-Open No. 2010-230954, evenwhen a member which is less liable to damage the surface of thephotosensitive drum is used for the protection member, the surface ofthe photosensitive member may be damaged by rubbing. In particular, whenan adhering matter is present on the protection member, the adheringmatter may damage the surface of the photosensitive drum.

When the photosensitive drum is to be replaced, the photosensitive drumis moved along the longitudinal direction of the LED print head. As inthe image forming apparatus disclosed in Japanese Patent ApplicationLaid-Open No. 2010-230954, when the LED print head and the surface ofthe photosensitive drum are arranged close to each other, the LED printhead may be brought into contact with the surface of the photosensitivedrum to damage the surface of the photosensitive drum. Therefore, whenthe photosensitive drum is to be replaced, it is necessary to separatethe photosensitive drum and the LED print head from each other. In sucha case, the photosensitive drum and the LED print head are separated bya large distance. For such an image forming apparatus, it is notpractical to clean the LED print head with use of the cleaning memberdisclosed in Japanese Patent Application Laid-Open No. 2010-230954.

The present invention has been made under such a circumstance, and hasan object to reliably clean an LED print head with use of a cleaningmember without providing a guide portion for the cleaning member to theLED print head.

SUMMARY OF THE INVENTION

The present invention has the following configuration to achieve theabove-mentioned object.

(1) An image forming apparatus, including: a photosensitive drum; an LEDprint head arranged along a longitudinal direction of the photosensitivedrum and configured to expose the photosensitive drum with light; a doorarranged on one end side of the LED print head in a longitudinaldirection of the LED print head and opened and closed when performingmaintenance; a support portion for the LED print head, the supportportion configured to operate in conjunction with opening and closingmovements of the door, configured to cause the LED print head to bepositioned at a first position for exposing the photosensitive drum withthe light under a state in which the door is closed, and configured tocause the LED print head to be positioned at a second position moreapart from the photosensitive drum than the first position under a statein which the door is open; and a guide portion formed on the door andconfigured to guide a cleaning member for cleaning the LED print head tothe LED print head, the guide portion having a first inclined surfacewhich is lowered toward the LED print head so that the cleaning member,which moves in the longitudinal direction of the LED print head, iscontinuously held in contact with the LED print head under a state inwhich the door is open and the LED print head is positioned at thesecond position.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view for illustrating a schematic configuration ofan image forming apparatus according to a first embodiment and a secondembodiment of the present invention.

FIG. 2 is a sectional view for illustrating a configuration of an LEDprint head of the first embodiment and the second embodiment.

FIG. 3 is a perspective view for illustrating a configuration of acleaning member of the first embodiment and the second embodiment.

FIG. 4 is a view for illustrating arrangement positions of the LED printhead of the first embodiment and the second embodiment.

FIG. 5 is a view for illustrating a positional relationship between animage forming portion and an inner door of the first embodiment and thesecond embodiment.

FIG. 6A is a view for illustrating a slide mechanism for the LED printhead of the first embodiment and the second embodiment under a state inwhich the inner door is closed.

FIG. 6B is a view for illustrating the slide mechanism for the LED printhead of the first embodiment and the second embodiment under a state inwhich the inner door is open.

FIG. 7A is a view for illustrating the slide mechanism for the LED printhead of the first embodiment and the second embodiment under the statein which the inner door is closed.

FIG. 7B is a view for illustrating the slide mechanism for the LED printhead of the first embodiment and the second embodiment under a state inwhich the inner door is open.

FIG. 8A is a side view for illustrating a configuration of a guideportion of the first embodiment.

FIG. 8B is a perspective view for illustrating a configuration of theguide portion of the first embodiment.

FIG. 9 is a view for illustrating a movement of the cleaning member ofthe first embodiment.

FIG. 10A is a side view for illustrating a movement of the cleaningmember of the first embodiment.

FIG. 10B is a view for illustrating a configuration of the LED printhead of the first embodiment.

FIG. 10C is a side view for illustrating a movement of the cleaningmember of the first embodiment.

FIG. 11A is a view for illustrating a configuration of a guide portionof the second embodiment.

FIG. 11B is a sectional view for illustrating a movement of the cleaningmember of the second embodiment.

FIG. 11C is a side view for illustrating a movement of the cleaningmember of the second embodiment.

DESCRIPTION OF THE EMBODIMENTS

Now, detailed description is made of embodiments of the presentinvention with reference to the drawings.

First Embodiment

Now, description is made of an embodiment of the present invention alongthe drawings.

[Configuration of Image Forming Apparatus]

FIG. 1 is a schematic sectional view of an image forming apparatus 100of an electrophotographic type according to a first embodiment of thepresent invention. The image forming apparatus 100 is an image formingapparatus of a so-called tandem type, which includes photosensitivemembers for respective colors including yellow (Y), magenta (M), cyan(C), and black (K) and is configured to superimpose images of therespective colors on an intermediate transfer member and collectivelytransfer the images onto a sheet. The image forming apparatus 100includes a sheet-feeding unit 101, image forming portions 102Y, 102M,102C, and 102K, an intermediate transfer belt 107, and a fixing device110. In the following, reference symbols Y, M, C, and K denoting colorsof toner are omitted unless otherwise needed.

The sheet-feeding unit 101 is configured to feed a sheet (also referredto as “recording sheet”) P and convey the sheet P to a secondarytransfer portion T2. The image forming portions 102Y, 102M, 102C, and102K are configured to form toner images of yellow (Y), magenta (M),cyan (C), and black (K) on photosensitive drums 103Y, 103M, 103C, and103K, respectively. The toner images formed on the photosensitive drums103 of the respective image forming portions 102 are transferred ontothe intermediate transfer belt 107. At the secondary transfer portionT2, the toner images on the intermediate transfer belt 107 arecollectively transferred onto the sheet P fed from the sheet-feedingunit 101. The fixing device 110 is configured to fix the unfixed tonerimages, which are transferred to the sheet P, onto the sheet P.

The image forming portions 102Y, 102M, 102C, and 102K of the imageforming apparatus according to the first embodiment have the sameconfiguration. Therefore, in the following, description is made of theimage forming portion 102Y. The image forming portion 102Y includes thephotosensitive drum 103Y being a photosensitive member, a chargingdevice 104Y configured to charge the photosensitive drum 103Y, an LEDprint head 105Y configured to expose the photosensitive drum 103Y withlight, and a developing device 106Y configured to develop anelectrostatic latent image on the photosensitive drum 103Y with use oftoner. The photosensitive drum 103Y is held in contact with theintermediate transfer belt 107 to form a primary transfer portion Tytogether with a primary transfer roller 108Y.

[Outline of Image Forming Process]

Description is made of an image forming process. When an image is to beformed, the charging device 104Y charges a surface of the photosensitivedrum 103Y to a uniform potential. The charged surface of thephotosensitive drum 103Y is exposed with light by the LED print head105Y being an exposure unit so that the electrostatic latent image isformed. The electrostatic latent image is formed into a visible image,that is, developed with yellow toner fed by the developing device 106Yso that the toner image is formed. At the primary transfer portion Ty,the primary transfer roller 108Y is arranged so as to be opposed to thephotosensitive drum 103Y. A predetermined transfer voltage is applied tothe primary transfer roller 108Y. With this action, the toner image onthe photosensitive drum 103Y is transferred onto the intermediatetransfer belt 107. Similarly, the toner images of the other colorsformed on the photosensitive drums 103M, 103C, and 103K are alsotransferred onto the intermediate transfer belt 107 by primary transferrollers 108M, 108C, and 108K arranged at primary transfer portions Tm,Tc, and Tk.

At the secondary transfer portion T2, a secondary transfer roller 109 isarranged so as to be opposed to the intermediate transfer belt 107. Apredetermined transfer voltage is applied to the secondary transferroller 109. With this action, the toner images on the intermediatetransfer belt 107 are transferred onto the sheet P being a recordingmedium conveyed from the sheet-feeding unit 101. The sheet P having thetoner images transferred thereon is conveyed to the fixing device 110.The unfixed toner image is heated and fixed on the sheet P by the fixingdevice 110. The sheet P subjected to the fixing processing by the fixingdevice 110 is delivered to a sheet delivery portion 111.

[Configuration of LED Print Head]

FIG. 2 is an enlarged schematic view for illustrating surroundings ofthe LED print head 105 of FIG. 1, and is a sectional view forillustrating a configuration of the LED print head 105 of the firstembodiment. The LED print head 105 has a shape of extending in adirection parallel to an axial center of the photosensitive drum 103(also referred to as “main scanning direction”). The LED print head 105includes an LED array 1, a rod lens array 2 (hatched portion in FIG. 2)configured to image light (broken lines in FIG. 2) emitted from the LEDarray 1 on the photosensitive drum 103, and a casing 3 being a supportmember configured to support the LED array 1 and the rod lens array 2.

In the LED array 1 being the light emitting element, LEDs correspondingto pixels of an image to be formed are substantially linearly mounted toa board 4 in a depth direction from a near side of FIG. 2. For example,when an image having a width of 300 mm is to be depicted with aresolution of 600 dpi, the total number of LEDs is 7,000 (=300mm×600/2.54 cm (1 inch)) or more. In the rod lens array 2, columnarlenses are arranged with regularity in the main scanning direction as inthe LED array 1. It is not always necessary that the number of lensescorrespond to the number of LEDs of the LED array 1. Erectequal-magnification images of the plurality of lenses are superimposedon one another to image the light emitted from the LEDs on thephotosensitive drum 103. A cross section along a short direction of thecasing 3, has an H-shape so that a relative distance between the board 4having the LED array 1 mounted thereto and the rod lens array 2 arrangedat a center of a cross bar in the H-shape is maintained with apredetermined accuracy. The casing 3 is manufactured with use of metalsuch as aluminum or with use of resin having a high rigidity. The board4 and the rod lens array 2 are fixed to the casing 3 by an adhesive. Inorder to prevent dust from entering the casing 3 and adhering to the LEDarray 1, a boundary portion between the casing 3 and the board 4 havingthe LED array 1 mounted thereto is closed by a seal material 5.Similarly, a boundary portion between the casing 3 and the rod lensarray 2 is closed by a seal material 6. On outer sides of the casing 3,there are provided wall portions 3 b which are higher than the exitsurface of the rod lens array 2.

[Configuration of Cleaning Member]

As illustrated in FIG. 2, an object-image distance TC of the rod lensarray 2, which is a distance from the exist surface of the LED array 1to the surface of the photosensitive drum 103, is approximately 10 mm.In this case, a distance Io from the exit surface of the rod lens array2 to the surface of the photosensitive drum 103 is only about 3 mm.Therefore, the distance between the photosensitive drum 103 and the rodlens array 2 is extremely small. In a periphery of the surface of thephotosensitive drum 103, part of toner fed by the developing device 106is not transferred to the photosensitive drum 103, that is, does notadhere to the photosensitive drum 103, and may fly in the atmosphere asdispersed toner. Therefore, when the image forming apparatus 100 isoperated continuously for a long period of time, the dispersed toner maypartially adhere to the exit surface of the rod lens array 2. When imageformation is performed in such a circumstance, the light from the exitsurface of the rod lens array 2 to which the toner adheres is blocked,with the result that an electrostatic latent image is prevented frombeing formed on the photosensitive drum 103. Therefore, a uniform imagedensity is not obtained, with the result that image defects such asstreaks and density unevenness may occur.

In order to avoid such a situation, a cleaning member configured to wipeoff the toner adhering to the rod lens array 2 of the LED print head 105is prepared. FIG. 3 is a perspective view for illustrating aconfiguration of a cleaning member 10 of the first embodiment. Thecleaning member 10 is a member having a configuration in whichanon-woven fabric 12 configured to wipe off dirt from the surface of therod lens array 2 is fixed to a distal end of a handle portion 11 being arod-like part made of soft resin such as polypropylene. The handleportion 11 has a protruding portion 13 having a reverse T-shaped crosssection. This cross-sectional shape enables insertion of the cleaningmember 10 into a groove portion 250 g of a guide portion 250 a (see FIG.5) provided to an inner door 250 (see FIG. 5) which is opened and closedat the time of maintenance work for the image forming apparatus 100. Asa result, the cleaning member 10 can easily be inserted into the grooveportion 250 g and can stably move in the groove portion 250 g. A user ora service worker can open the inner door 250 provided to a front surface(near side in FIG. 1) of the casing of the image forming apparatus 100and clean the rod lens array 2 of the LED print head 105 with use of thecleaning member 10.

[Slide Mechanism for LED Exposure Unit]

FIG. 4 is a view for illustrating arrangement positions of the LED printhead 105, and is an enlarged sectional view of the image forming portion102 of the image forming apparatus 100 according to the firstembodiment. In FIG. 4, the photosensitive drum 103 and the chargingdevice 104, which are described with reference to FIG. 1, are integratedin a drum cartridge 200. A developing unit 201 is a unit which is thesame as the developing device 106. The arrangement positions of the LEDprint head 105 include a position (I) being a first position close tothe photosensitive drum 103 and a position (II) being a second positionapart from the photosensitive drum 103. Under a state in which the innerdoor 250 is closed, that is, when an image forming operation isperformed, the LED print head 105 is arranged at the position (I) andforms an electrostatic latent image on the photosensitive drum 103 inaccordance with an image signal. When the LED print head 105 is arrangedat the position (I) at the time of maintenance work such as unitreplacement, the drum cartridge 200 is caught by the LED print head 105and cannot be drawn out. Therefore, the image forming portion 102includes a slide mechanism configured to cause the LED print head 105 tomove from the position (I) to the position (II) when the inner door 250is opened at the time of maintenance work or the like. FIG. 5 is a viewfor illustrating a positional relationship between the image formingportion 102 and the inner door 250 which is opened and closed at thetime of maintenance. FIG. 5 is an illustration of the positionalrelationship when the image forming portion 102 is viewed from a leftside in FIG. 1. The arrows of FIG. 5 indicate directions in which theinner door 250 can be opened and closed through an opening and closingoperation. In FIG. 5, a standing state of the inner door 250 indicatesthe closed state of the inner door 250 with the solid lines, and a lyingstate of the inner door 250 indicates the open state of the inner door250 with the broken lines. In the first embodiment, the drum cartridge200 cannot be drawn out unless the inner door 250 provided at theposition opposed to the image forming portion 102 as illustrated in FIG.5 is opened. As described above, the LED print head 105 moves to theposition (I) being an exposure position under the state in which theinner door 250 is being closed, and the LED print head 105 moves to theposition (II) being a retreated position under the state in which theinner door 250 is being opened. The LED print head 105 can reciprocatebetween the two positions in conjunction with the opening and closingmovements of the inner door 250. The inner door 250 is provided at theposition opposed to the image forming portion 102 for each image formingportion 102.

FIG. 6A and FIG. 6B are perspective views for illustrating a mechanismof the slide mechanism configured to cause the LED print head 105 toreciprocate between the position (I) and the position (II). FIG. 6A is aperspective view for illustrating a state of the LED print head 105under the state in which the inner door 250 is closed. FIG. 6B is aperspective view for illustrating a state of the LED print head 105under the state in which the inner door 250 is open. On a back side ofthe inner door 250, which is a side opposed to the LED print head 105under the state in which the inner door 250 is closed, there is provideda standing wall 250 c being a standing wall portion which stands on theinner door 250. The standing wall 250 c and an end portion of a lifter251, which constructs the slide mechanism configured to cause the LEDprint head 105 to reciprocate between the position (I) and the position(II), on the inner door 250 side are connected to each other by links252 being a pair of connection rods. The lifter 251 being a supportportion for the LED print head 105 has slopes being two inclinedsurfaces. The two inclined surfaces include a slope 251 a formed in afront portion (side close to the inner door 250) of the lifter 251 inthe longitudinal direction, and a slope 251 b formed in a rear portion(side apart from the inner door 250) of the lifter 251 in thelongitudinal direction. The LED print head 105 placed on the lifter 251moves along the inclined surfaces while being held in abutment againstthe slopes 251 a and 251 b of the lifter 251. Therefore, the LED printhead 105 has leg portions 105 a and 105 b for reciprocation between theposition (I) and the position (II).

FIG. 6A is an illustration of the state in which the inner door 250 isclosed, that is, the state in which the inner door 250 stands. At thistime, the LED print head 105 is in the state of being arranged at theposition (I) of FIG. 4. When the inner door 250 is opened, that is,moved in the arrow direction from the state in which the inner door 250is closed, that is, from the state in which the inner door 250 stands,the inner door 250 is rotated in the arrow direction about a pair ofprojection portions 250 d as rotation centers. Along with this action,the lifter 251 moves in the arrow direction through intermediation ofthe links 252 connected to the standing wall 250 c of the inner door250. When the lifter 251 moves in the arrow direction, the leg portions105 a and 105 b of the LED print head 105 placed on the lifter 251 movealong the inclined surfaces of the slopes 251 a and 251 b of the lifter251. Then, the LED print head 105 is lowered in the arrow direction.FIG. 6B is an illustration of a state in which the leg portions 105 aand 105 b of the LED print head 105 are completely lowered along theinclined surfaces of the slopes 251 a and 251 b of the lifter 251. Atthis time, the LED print head 105 is in the state of being arranged atthe position (II) of FIG. 4.

When the inner door 250 is closed from the open state illustrated inFIG. 6B, the lifter 251 moves in a direction reverse to the arrowdirection of FIG. 6A, that is, in a direction of separating from theinner door 250 through intermediation of the links 252 connected to theinner door 250. With this action, the leg portions 105 a and 105 b ofthe LED print head 105 move in an upward direction in FIG. 6B along theinclined surfaces of the slopes 251 a and 251 b of the lifter 251. Then,the LED print head 105 is raised and shifted to the state of beingarranged at the position (I) of FIG. 4.

FIG. 7A and FIG. 7B are side views for illustrating states of the LEDprint head 105 and the inner door 250 when the states of the perspectiveviews of FIG. 6A and FIG. 6B are viewed from the left side in FIG. 1.FIG. 7A corresponds to FIG. 6A, and FIG. 7B corresponds to FIG. 6B.Movements of the LED print head 105 and the lifter 251 during theopening and closing operations of the inner door 250 are the same asthose described with reference to FIG. 6A and FIG. 6B, and hencedescription thereof is omitted. The reciprocation mechanism for the LEDprint head 105 is not limited to the mechanical link mechanismillustrated in FIG. 6A, FIG. 6B, FIG. 7A, and FIG. 7B. The reciprocationmechanism may be, for example, an electrical mechanism, which includesan opening and closing detection sensor at the inner door 250 and isconfigured to raise and lower the LED print head 105 with power of amotor or the like.

[Posture Control for Cleaning Member]

When the LED print head 105 is arranged at the position (I) (see FIG. 4)being the arrangement for image formation (image forming), a distancebetween the photosensitive drum 103 and the LED print head 105 is onlyabout 3 mm, and there is no space for allowing insertion of the cleaningmember 10. When the cleaning member 10 is forcibly inserted, thecleaning member 10 is brought into contact with the photosensitive drum103, with the result that the photosensitive drum 103 may be damaged.Therefore, the LED print head 105 is cleaned when the LED print head 105is arranged at the position (II) in the retreated state. Typically, aguide portion configured to bring the cleaning member 10 into abutmentagainst the rod lens array 2 at the time of cleaning is required.However, before the LED print head 105 retreats to the position (II),there is a space of only 3 mm between the LED print head 105 and thephotosensitive drum 103 at the time of image forming. Therefore, such aspace is too narrow to provide the guide portion for the cleaning member10 in the vicinity of the rod lens array 2 of the LED print head 105.

[Shape of Guide Portion]

Therefore, in the first embodiment, the guide portion 250 a is providedon an inner side of the inner door 250, that is, on a side opposed tothe LED print head 105. The guide portion 250 a is a guide portionconfigured to regulate posture of the cleaning member 10, which moves inthe longitudinal direction of the LED print head, to reliably clean therod lens array 2 of the LED print head 105. FIG. 8A and FIG. 8B areillustrations of a shape of the guide portion 250 a provided to theinner door 250. FIG. 8A and FIG. 8B are illustrations of a state of theinner door 250 when the cleaning member 10 is used, that is, a state ofthe inner door 250 when the LED print head 105 is arranged at theposition (II). In FIG. 8A and FIG. 8B, the links 252 are omitted.

The side view illustrated in FIG. 8A is an illustration of a state ofthe inner door 250 as viewed from the left side in FIG. 1. The guideportion 250 a is provided at a head top portion of the standing wall 250c which stands on the inner door 250. As illustrated in FIG. 8A, theguide portion 250 a has a slope shape (first inclined surface) beinginclined in a downward direction toward the LED print head 105. An angleof the slope of the guide portion 250 a is set so that the non-wovenfabric 12 provided at a distal end of the cleaning member 10 is broughtinto abutment against the casing 3 of the LED print head 105 when thecleaning member 10 inserted into the groove portion 250 g of the guideportion 250 a proceeds along the shape of the groove portion 250 g. Asillustrated in FIG. 8B, the groove portion 250 g having a reverseT-shaped cross section is formed in the guide portion 250 a. Thecleaning member 10 is oriented obliquely in the downward direction andinserted into the groove portion 250 g of the guide portion 250 a, andthen is pushed. Accordingly, the cleaning member 10 proceeds along thegroove portion 250 g of the guide portion 250 a. Therefore, deviation ofthe cleaning member 10 in upward, downward, rightward, and leftwarddirections is regulated by the groove portion 250 g. As a result, themovement of the cleaning member 10 is stabilized, thereby being capableof allowing the cleaning member 10 to proceed in the direction towardthe LED print head 105 without deviation.

FIG. 9 is a perspective view for illustrating a state in which thecleaning member 10 inserted into the groove portion 250 g of the guideportion 250 a reaches an end portion of the LED print head 105 on theinner door 250 side. In FIG. 9, the links 252 are omitted. Asillustrated in FIG. 9, the cleaning member 10 is inserted into thegroove portion 250 g of the guide portion 250 a, and the handle portion11 of the cleaning member 10 is pushed in the direction toward the LEDprint head 105. With this action, the cleaning member 10 moves in thedirection toward the LED print head 105 along the slope of the guideportion 250 a. As a result, the cleaning member 10 is guided to the LEDprint head 105 by the groove portion 250 g of the guide portion 250 a.Then, the non-woven fabric 12 provided at the distal end of the cleaningmember 10 is brought into abutment against the LED print head 105. Thehandle portion 11 of the cleaning member 10 has a reverse T-shaped crosssection, and is inserted into the groove portion 250 g, which has thereverse T-shaped cross section, of the guide portion 250 a. Thus, thehandle portion 11 is regulated by the shape of the groove portion 250 g.With this configuration, the cleaning 10 is guided in the directiontoward the LED print head 105 without deviation in the upward, downward,rightward, and leftward directions.

FIG. 10A is a side view for illustrating a state of the cleaning member10 illustrated in FIG. 9 as viewed from the left side in FIG. 1. FIG.10B is an enlarged view for illustrating surroundings of an end portionof the casing of the LED print head 105 on the inner door 250 sideagainst which the non-woven fabric 12 of the cleaning member 10 is heldin abutment in FIG. 10A. A guide slope 3 a is provided at an end portionof the casing 3 of the LED print head 105 on the inner door 250 side(door side). The guide slope 3 a has an inclined surface, which isinclined in the upward direction in FIG. 10B toward the rod lens array 2and is configured to guide the non-woven fabric 12 of the cleaningmember 10 to the rod lens array 2. The guide slope 3 a causes thenon-woven fabric 12 provided at the distal end of the cleaning member 10to be raised in the upward direction in FIG. 10A. With this action, thecleaning member 10 is urged in the downward direction in FIG. 10A, thatis, in the direction toward the LED print head 105. Wall portions 3 bare provided to the casing 3. The non-woven fabric 12 of the cleaningmember 10 is regulated by the wall portions 3 b in therightward-and-leftward direction (horizontal direction) in FIG. 10B,which is orthogonal to a proceeding direction of the cleaning member 10.With this action, deviation of the cleaning member 10 in the horizontaldirection is prevented.

FIG. 10C is an illustration of a state in which the cleaning member 10is further inserted in the direction toward the LED print head 105 fromthe state of FIG. 10A. The portion indicated by the broken linecorresponds to the cleaning member 10. As illustrated in FIG. 10C, whenthe non-woven fabric 12 of the cleaning member 10 is held in abutmentagainst the rod lens array 2 of the LED print head 105 to clean the rodlens array 2, the cleaning member 10 is entirely warped in the downwarddirection in FIG. 10C. That is, fluttering of the cleaning member 10 inthe upward-and-downward direction is regulated by the guide portion 250a of the inner door 250, and the cleaning member 10 is raised in theupward direction by the guide slope 3 a of the casing 3. With thisaction, the cleaning member 10 is entirely urged in the downwarddirection in FIG. 10C. As a result, the non-woven fabric 12 provided atthe distal end of the cleaning member 10 is also urged in the downwarddirection in FIG. 10C, that is, in the direction toward the rod lensarray 2. Therefore, the surface of the rod lens array 2 can reliably bewiped. A force of urging the non-woven fabric 12 in the direction towardthe rod lens array 2 is larger than a force of urging the handle portion11 in the direction toward the rod lens array 2. The non-woven fabric 12of the cleaning member 10 is guided between the wall portions 3 bprovided on both sides of the casing 3. Therefore, the non-woven fabric12 can reciprocate on the surface of the rod lens array 2 while reliablycleaning the rod lens array 2 without being separated from the rod lensarray 2.

As described above, according to the first embodiment, the cleaningmember is capable of reliably cleaning the LED print head withoutproviding the guide portion for the cleaning member to the LED printhead.

Second Embodiment

In the first embodiment, the shape of the guide portion 250 a providedto the inner door 250 is set so as to allow the cleaning member 10 to beinserted obliquely from the upper side to the lower side. In the secondembodiment, description is made of a shape of the guide portion whichenables the LED print head 105 to be reliably cleaned by only causingthe cleaning member 10 to reciprocate in the horizontal directionwithout need of being aware of the angle of insertion of the cleaningmember 10.

[Shape of Guide Portion]

FIG. 11A is a perspective view for illustrating a shape of a guideportion 250 b provided to the inner door 250 of the second embodiment.FIG. 11B is a sectional view of the inner door 250 including the guideportion 250 b as viewed from the left side in FIG. 1. In FIG. 11A, FIG.11B, and FIG. 11C, the links 252 are omitted. As illustrated in FIG.11A, similarly to the guide portion 250 a of the first embodiment, theguide portion 250 b is provided at a head top portion of the standingwall 250 c which stands on the inner door 250. Further, similarly to thefirst embodiment, a groove portion 250 h having a reverse T-shaped crosssection is formed in the guide portion 250 b. When the LED print head105 is to be cleaned, the cleaning member 10 is inserted into the grooveportion 250 h.

As illustrated in FIG. 11B, the guide portion 250 b has a horizontalportion 250 e being a horizontal surface and a slope portion 250 f(first inclined surface) being an inclined surface connected to thehorizontal portion 250 e. As indicated by the arrow in FIG. 11B, thedirection of inserting the cleaning member 10 toward an inlet side ofthe guide portion 250 b is a horizontal direction, which is differentfrom the oblique direction of the first embodiment. Therefore, thenon-woven fabric 12 provided at the distal end of the cleaning member 10is inserted into the guide portion 250 b in the horizontal direction andproceeds under the horizontal portion 250 e. The slope portion 250 fbeing continuous from the horizontal portion 250 e has an inclinationwhich causes the distal end of the cleaning member 10 to be oriented inthe downward direction. This inclination has an angle which causes thenon-woven fabric 12, which proceeds under the slope portion 250 f, to bebrought into abutment against the guide slope 3 a (second inclinedsurface) of the casing 3 of the LED print head 105. A distance between aposition at which the distal end of the cleaning member 10 is orientedin the downward direction and a position of the casing 3 of the LEDprint head 105 is smaller than that of the first embodiment. Therefore,the angle of inclination of the slope portion 250 f is larger than theangle of inclination of the guide portion 250 a of the first embodiment.

FIG. 11C is a side view for illustrating a state in which the cleaningmember 10, which is inserted into the groove portion 250 h of the guideportion 250 b, reaches the guide slope 3 a of the casing 3 of the LEDprint head 105. The portion indicated by the broken line corresponds tothe cleaning member 10. As illustrated in FIG. 11C, the cleaning member10 which proceeds in the groove portion 250 h of the guide portion 250 bis deformed into a substantially S-shape and is brought into abutmentagainst the LED print head 105. Also in the second embodiment,fluttering of the cleaning member 10 in the upward-and-downwarddirection is regulated by the guide portion 250 b of the inner door 250,and the cleaning member 10 is raised in the upward direction by theguide slope 3 a of the casing 3. With this action, the cleaning member10 is entirely urged in the downward direction in FIG. 11C. Inparticular, in the second embodiment, the inclination of the slopeportion 250 f of the guide portion 250 b is larger than the inclinationof the guide portion 250 a of the first embodiment. Therefore, the forceof urging the cleaning member 10 is larger than that of the firstembodiment. As a result, the non-woven fabric 12 provided at the distalend of the cleaning member 10 is also urged in the downward direction inFIG. 11C, that is, in the direction toward the rod lens array 2.Therefore, the surface of the rod lens array 2 can reliably be wiped.The non-woven fabric 12 of the cleaning member 10 is guided between thewall portions 3 b provided on both the sides of the casing 3. Therefore,the non-woven fabric 12 can reciprocate on the surface of the rod lensarray 2 while reliably cleaning the rod lens array 2 without beingseparated from the rod lens array 2. As a result, a user or a serviceworker can clean the rod lens array 2 of the LED print head 105 by onlycausing the cleaning member 10 to reciprocate in the horizontaldirection without need of being aware of the angle of insertion of thecleaning member 10.

As described above, according to the second embodiment, the cleaningmember is capable of reliably cleaning the LED print head withoutproviding the guide portion for the cleaning member to the LED printhead.

[Effect of Invention]

According to the present invention, the cleaning member is capable ofreliably cleaning the LED print head without providing the guide portionfor the cleaning member to the LED print head.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2016-196480, filed Oct. 4, 2016, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image forming apparatus, comprising: aphotosensitive drum; an LED print head arranged along a longitudinaldirection of the photosensitive drum and configured to expose thephotosensitive drum with light; a door arranged on one end side of theLED print head in a longitudinal direction of the LED print head andopened and closed when performing maintenance; a support portion for theLED print head, the support portion configured to operate in conjunctionwith opening and closing movements of the door, configured to cause theLED print head to be positioned at a first position for exposing thephotosensitive drum with the light under a state in which the door isclosed, and configured to cause the LED print head to be positioned at asecond position more apart from the photosensitive drum than the firstposition under a state in which the door is open; and a guide portionformed on the door and configured to guide a cleaning member forcleaning the LED print head to the LED print head, the guide portionhaving a first inclined surface which is lowered toward the LED printhead so that the cleaning member, which moves in the longitudinaldirection of the LED print head, is continuously held in contact withthe LED print head under a state in which the door is open and the LEDprint head is positioned at the second position.
 2. An image formingapparatus according to claim 1, wherein a standing wall portion whichincludes the guide portion is formed on the door, wherein an end portionof the support portion and an end portion of the standing wall portionof the door are connected to each other through intermediation of aconnection rod which is connected to the support portion and thestanding wall portion, wherein the support portion has an inclinedsurface along which the LED print head placed on the support portionmoves, wherein, when the door is opened from the closed state, thesupport portion moves in a direction of approaching the door so that theLED print head placed on the support portion is lowered from the firstposition along the inclined surface of the support portion to move tothe second position, and wherein, when the door is closed from the openstate, the support portion moves in a direction of separating from thedoor so that the LED print head placed on the support portion is raisedfrom the second position along the inclined surface of the supportportion to move to the first position.
 3. An image forming apparatusaccording to claim 2, wherein the guide portion has a groove portioninto which the cleaning member is inserted, wherein the groove portionhas a first inclined surface, and wherein a distal end of the cleaningmember proceeds in the groove portion along the first inclined surfaceto be brought into contact with an end portion of the LED print head,which is opposed to the door.
 4. An image forming apparatus according toclaim 2, wherein the guide portion has a groove portion into which thecleaning member is inserted, wherein the groove portion has a horizontalsurface, which is arranged on an inlet side of the groove portion intowhich the cleaning member is inserted, and the first inclined surfaceconnected to the horizontal surface, and wherein a distal end of thecleaning member proceeds in the groove portion along the first inclinedsurface to be brought into contact with an end portion of the LED printhead, which is opposed to the door.
 5. An image forming apparatusaccording to claim 3, wherein the cleaning member includes a handleportion and non-woven fabric which is arranged at a distal end of thehandle portion and is configured to wipe off dirt on the LED print head.6. An image forming apparatus according to claim 5, wherein the grooveportion of the guide portion has a reverse T-shaped cross section, andwherein the handle portion of the cleaning member has a reverse T-shapedcross section to enable insertion into the groove portion.
 7. An imageforming apparatus according to claim 6, wherein the LED print headcomprises: a plurality of LEDs configured to emit light; a lensconfigured to image light emitted from the plurality of LEDs onto thephotosensitive drum; and a support member configured to support theplurality of LEDs and the lens, wherein the support member has a secondinclined surface which is arranged at an end portion thereof opposing tothe door, with which the non-woven fabric of the cleaning member guidedby the guide portion is contact, and which is configured to guide thenon-woven fabric to the lens, and wherein the second inclined surface israised toward a direction of separating from the guide portion.
 8. Animage forming apparatus according to claim 7, wherein a force of urgingthe non-woven fabric toward the lens by the first inclined surface andthe second inclined surface is larger than a force of urging the handleportion toward the lens by the first inclined surface and the secondinclined surface.
 9. An image forming apparatus according to claim 8,wherein the support member has wall portions, which extend toward thephotosensitive drum, on both sides of the lens in a short direction ofthe lens, and which are configured to regulate deviation of the cleaningmember in a horizontal direction orthogonal to a proceeding direction ofthe cleaning member.